Hanger insert for steel floor deck

ABSTRACT

An elongate bolt having a head at its upper end and a threaded lower end is mounted through a sheet steel member of a steel floor deck. The threaded lower end may comprise a stud formation or an interior threaded socket. The bolt is mounted in a hole drilled in the horizontal sheet steel member and is held in place by a thin flexible sheath member engaging the bolt below the sheet of steel and a flat leaf spring engaging the upper surface of the sheet of steel. When concrete is poured on the upper surface of the horizontal sheet steel member and set, it will embed the upper portion of the bolt which may have additional structural means to increase the embedded area. Prior to pouring, however, the upper portion of the bolt is yieldable by reason of the flat leaf spring but recoverable to a position perpendicular to the plane of the sheet steel member.

United States Patent 191 Werstein et al.

[ July'29, 1975 HANGER INSERT FOR STEEL FLOOR DECK [75] Inventors: Frank A. Werstein, Long Beach;

William R. Barnes, Highland, both of Ind.

[73] Assignee: International Telephone and Telegraph Corporation, New York, NY.

[22] Filed: Aug. 2, 1973 [21] Appl. No.: 384,968

Related US. Application Data [63] Continuation of Ser. No. 214,226,-Dec1 30, 1971,

abandoned.

52 US. c1 52/704; 52/39 511 Int.Cl. G09F7/18 [58] Field of Search 52/39, 699,698,700, 701;.

[56] References Cited UNITED STATES PATENTS 1,072,361 9/19l3 Rickman 52/706 X Fitzgerald 85/50 R Holt 52/706 X 3,769,774 11/1973 Barnes ..52/39X Primary Examiner-Frank L. Abbott Assistant Examiner-Carl D. Friedman Attorney, Agent, or Firm-J. B. Raden; D. P. Warner [57] ABSTRACT An elongate bolt having a head at its upper end anda threaded lower end is mounted through asheet steel member of a steel floor deck. The threaded lower end may comprise a stud formation or an interior threaded socket. The bolt is mounted in a hole drilled in the horizontal sheet steel member and is held in place by a thin flexible sheath member engaging the boltbelow the sheet of steel and a flat leaf spring engaging the 22 Claims, 8 Drawing Figures HANGER INSERT FOR STEEL FLOOR DECK This is a continuation of application Ser. No. 214,226, filed Dec. 30, 1971, now abandoned.

BACKGROUND OF THE INVENTION The invention herein is concerned with apparatus which is intended to be installed in the deck of a building during the construction thereof to provide depending hangers below the deck. For example, through the use of the hanger inserts of the invention, one may support pipes and conduits, automatic sprinkler apparatus,

electrical fixtures, and any other apparatus which would normally be depending from a ceiling.

What will be referred to herein as deck construction or decking is a type of construction which is extensively.

used for forming the floors of large steel frame buildings of multiple stories. The floor of one level isdefined on the upper surface of a givendeck while the ceiling of the lower level is defined by the lower surface of the same deck.

Although there are several types of deck construction in use today in the construction of large buildings, one of the most important of these is the steel floor deck due to its presently increased use in large steel frame buildings of multiple stories.

Fluted or corrugated sheet steel is utilized as a floor base and filled with a substantial layer of concrete poured in situ. Utility service conduits are laid insuitable formations of the sheet steel member prior to pouring concrete upon the upper surface .of the member. There may be outlets for these conduits on the upper surfaces of the concrete layer which are prelocated in the concrete or otherwise identified to be used at a later time. The bottom of this layer of concrete is in intimate contact with the steel base whose underside is exposed below'as the ceiling for the lower level. The resulting deck structure is strong and ,substantiallyfireproof.

In the planning of a building, structures to be supported from the bottom of the deck are best located and inserts installed in the sheet steel prior to pouring the concrete. The only alternative is to attempt to efbody having its lower end constructed to secure a structural member thereto, its upper end provided with a head or other enlarged means to be embedded in concrete, the boltlike member being secured to a horizontal sheet steel member with a flexible or yieldable connection. A thin flexible sleevelike member of sheet metal or elastomeric material is secured to the boltlike member below the sheet steel member and a flat leaf spring is engaged against the upper surface of the sheet steel member and held to the elongate boltlike member.

Different means are-utilized to assemble the several partsof the hanger so that it may readily swing or yield and return to its original vertical position perpendicular to the horizontal sheet steel member even though struck or moved by a workman or an object prior to thev pouring of the concrete.

Once the concrete has been poured, the upper portion of the boltlike member is permanently embedded I and the lower end thereof extends below the sheet steel member and is available for securement of structural members thereto. Either a stud arrangement or a I threaded socket may be provided.

BRIEF'DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary sectional view taken through the latter being shown, for the most part, in elevation; FIG. 2 is a sectional view taken through the hanger insert of FIG. 1 generally along the line 2-2 and lookfeet the installation from below after the concrete has I set. This is a difficult and expensive technique. One

must first cut or drill through the layer of steel and then use some form of'concrete anchor.

The invention contemplates a type of hanger insert which obviates some problems arising in any attempt to provide hanger inserts for pre-installation.

First, the insert must be simple andstrong so that it can be installed effectively and easily. Also, it must be economical and result in a strong installation below the deck after the concrete has set.

Secondly, the insert must not readily be pulled out or permanently bent over prior to the pouring of the concrete. This is important because until the concrete has been fully poured, workmen may step on the inserts,

accidentally kick them, or structures to be preset into. the concrete may be moved against the inserts. The latter structures might be utility conduits or reinforcing rods.

Certain other problems in connection with'such hanger inserts are solved by the invention as'will be seen.

SUMMARY OF THE INVENTION The hanger insert comprises an elongate boltlike ing upwardly;

FIG. 3 is a perspective view of the sheath member of the structure of FIG. 1;

FIG. 4 is a fragmentary view illustrating a modified form'of the invention using a sheath member which is different from that illustrated in FIG. 1;

FIG. 5 is a side elevational view with portions in section as showing a further modified form of the invention;

FIG. 6 is a bottom plan view of the sleeve member of FIG. 5;

. FIG. 7 is a sectional view through the sleeve member of FIG. 6 taken generally along the line 77 and in the direction indicated; and

FIG. 8 is a view similar to that of FIG. 1 showing a further modified form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As previously explained, the hanger insert of the invention is designed to be installed in decking of the type which involves poured concrete prior to the pouring of the concrete so that the setting of the concrete will permanently anchor the insert in the deck.

In FIG. .1 there is illustrated a portion of a steel floor deck comprising a horizontal'sheet steel member 10 having a layer of concrete 12 of substantial thickness above the same and in intimate contact therewith. The hanger insert of the invention is designated generally by the reference character 14 and is shown partially above and partially below the horizontal sheet steel member 10.

The insert 14 comprises an elongate boltlike member having an upper cylindrical body portion 16 and a lower cylindrical body portion 18, the lower body portion 18 protruding below the sheet steel member 10 maydrop; t 1 After theinsert has 1A sheathmember 28 is provided to securethe boltlike member to th e'sheet steel member 10; The sheath member28 is best illustrated in FIG 31. lt is a sleevelike' structure formed from thin sheet spring-steel and has a' cylindrical body 30o'pen atthe bottom as shown at132 and'providecliwith an axial; s arse therehy givingthe sheath member hodilyresilience; At its upper there i v are providedflangelike ears'36'jand aplurality ofispring L finger-s38 spacedrbelowthe" 6211 8436. Theispringfin 'gers y are formedby puhching thesaine outiof slots 40"pr0' yided in the body30'of the-sheath me brjandhavean.

e xternal hemil 42 that" protrudesoutwardlyaof "the body;

iz on'tal sheet'steettmernber l asshownat tflg this hole cient'spa'ce forfcornpress'ing' the sheath 28in1order to Q force it into "the hole J46; Theioutwardly jextending bends 42 of the fingers 38must becompres'sed in fore: V

on the upper surfaceof the sheet steel mem'berllfl the position shown in FIG. 1. a

The upper portion 16 of r e boltlike member is 5 'vided adjacent its center with proturberances 48 which maybe formed simplyby' pinching the metal at this pointfA flat leaf spring 50 which is bowedrinr a com cavely downward direction hasja Central opening 52G and isfitted to the portion 16' 'of'the boltlike member.

The ends are slightlyturnedtup 'at SL The lower portion,l8 of the boltlikemember is" inserted through'the opening 52 and thereafter pushed into the sheath meming the she'ath member 28 downwardly through the hole; 46 and they spring back when the ears 36 engage r 7 FIG; 8 'illustrates a ber'28. The lower end of the sheath member ZS may, t have inturned lips as shown at 54 tolimit the extent to a which the lower'portion 18 may enter, or there may be a groove suchas shown which vutilizes a Sheathmember ZS' that has'anextension 60 terminating in an end cap 62.The end cap 62 V limits the extent to which the lower portion 18 of the the threaded'socket ,20' until use at which time the workmen may break off the cap'62 or bendthe sameg 1 aside i n orderto have access to the threaded socrketx at'Sfi into which the fingers V been'assembled asshown inFlG;

t1, itis'ca'pable of being'rocked or otherwisemoved tof, acer'tain extend by workmen kickingor stepping onthe san'ieand it will recover to'its vertical positio n perpendicular to the plane of the sheet'steel member 10.

When the concrete is poured around: the same, it will aontemntited -a with "iateahythingffrorn the bottom of t her 36.; in: t and anintern'alf edge 4 4 on the interior'of the body 30. i i ln installin'g the insert,firstaholeis drilledihth e;hot being ofatdi'ameter slightly lessthantthe diameter re the body portion 30'. co'uldieven be the sa'niegdiamen 'ter or slightlylar ger sot-that the split34 pfovidess'uffi- 88 is'engaged'on the lower-portion 900i the bolt; 1

ofrthe; sheet metal member "8 the positionishown Sotha't V is ay; th efworl inst lling; the insert assembles t e same practically as shown and tforcesthe bottom'lend together withfthel nut 88 throu thence; 84'. Theearst94contract and fthen sp riug outwardly "afterpassingthroughtheholef84tThe firmhessof H165? 'leaf spring- :76 isteasily adjusted by taking D 616355 mg the 'nut .80. "As inthe e as of; t e: previouslyi'fde 1 scribed teatsspringr'thelends"98 arefslightlyl bent to ens "able; considerable latitude QfJmOVe'r'neritL lfthie 'ins ertf"Q dis stepped 011,11; will recover by virtuelot 'theleaf spring; V

7 or'ifitis struck fromthe side laterally, itwill erectitself i when the 'pre ssure'i's removed. i t a "ff In 'thisicasqtheportion acts' like'h stud which is tprotrudingfrom'thebottom of the sheet steel member V a a W 86 which forms the ceiling for thelevel below the deck;

Either a structural member may be seejur'ed to the porti0n=90 by aconventiohainutuorfan elongateiadapter I a nut may .be screwed meme end 90-to provide (a socketin its bottom end'torec'eive threaded structural members.

Ifof'the hole 46 lockingly engage i n one of thegrooves "boltlik'e member 14 may be inserted and it: also protects fFlG. 5 illustrates a relatively simpleform of them vention which comprises a threaded "bolt lfl having a' 116 while'the spring Ellis en'gagedagainst stops 48 v under some tension.

The structure of FIG. 8 functions like the others;

When theconcrete is set, the elastomeric wall 1 M is ail that is exposed belowthedeck. The stude'nd 18 is'pro," a I tected until the wOrkr'na Wa ts touse it. Hecantheni it pull off the'par't of the sheathft w'protruding or cutfit L away; Prior to pouring o theconcretej therbolttl'will I #readily yield laterally if struckandi willalso providqa 1 alargewasherfl t onneeted" V i to theheacl toig'ive:azlargerfarea' ofembedment; Thegy,

' same type of leaf springaspreviously describedis' used a I 1 this bein g shownaat. 76Qhaying -a central opening 78 5 n which engages {the upper body 82 ofthejbolt 70, its po-t g 'sition; being determined by thel out; titl engaging the a f, u p r ithr'eade'djportion 83 of he bolt 70;, The iower end of the holt'passes'thtough an opening 84Yin the. a sheet steeljmembert86andasheet metal sleevelik'e nut l f I resiliencfeotthe flared sheet metaliittiem mfldified forrnof the invention" I 7 similar to those formsshown but using a sheathrnerm: her which is'moldedfr om anel'astomersuch,aSnau,1 ural or synthetie rubberjor elasticresins; Theholt 'M 7 has PPPer'bOdY Portidntltiandja lowerbodyportion", I 137 which in this caseisan externallythreaded stud end 1 n separated fro'm the upper bod y por tion by azshoulder v j llZqThe sheath member 1 10 has a relatively thin wall 1 a' I V a a V 114 theexterior ofhwhi chi isr tapered aeshown 'with ar a 4 plurality of ridges 115 fotmingfgroove's ll ofirtcream 'ingldiameter,upwardly. Therbolt 14"is, inserted mother v a sheath ,ll0hwhichtightly engages the 'stud end li8", thei spring, Bob/being in place The lower end i t fi of lthea i 'shea'this introduced in o the hole 46 previously cutin V thesteel deck 10 fromjabove; Theworltman pushesth'e a sheath ltflfand studend 18intojtheiholeiuntil the lips;

degree of axial yielding as well, recovering to its vertical position when the disturbing force is removed.

Modifications of the invention may be made without departing from the spirit or scope of the same asdefined in the appended claims.

What it is desired to secure by Letters Patent of the United States is: a

1. A hanger insert for installation in decking including a layer of concrete and a sheet member supporting in a dispositionpassing through a hole in a sheet member which is adapted to have concrete poured onto the upper surface of the sheet member, with the bottom portion of the elongate metal member protruding below the sheet member and the top portion of the elongate metal member protruding above the sheet member,

C. said elongate metal member including structure to enable the securement of a structural member from the bottom portion thereof which structural member is adapted to depend from the decking to be formed, and

D. a leaf spring formed of flat spring stock bowed about a central area and loosely mounted through said central area on said elongate member to have its concave surface facing the lower portion of the I elongate member, said leaf springbeing held between the stop means on said elongate member and the upper surface of said sheet member, said leaf spring providing a yieldable connection between portion integral with said elongate metal member, said.

leaf spring has a central opening in which said elongate metal member engages, and said formation is larger than said opening.

3. The hanger insert as claimed in claim l, in.which the elongate metal member is a threaded bolt, the leaf spring has a central opening in which said bolt is engaged, and the stop member is a nut, the structure to enable securement comprising the bottom threaded end of said bolt. I

4. The hanger insert as claimed in claim 1, in which the upper end of said elongate metal member comprises an enlarged structure to provide embedment.

area greater than the cross-sectionalarea of said elongate metal member. g

5. The hanger insert as claimed in claim 1, in which the means for supporting the elongate member include a sleevelike sheet metal member secured on said lower portion and adapted to engage the bottom surface of said sheet member and clamp same between'said leaf spring and itself.

6. The hanger insert as claimed in claim 5, in which the ends of the leaf spring are turned slightly toward the upper portion of the elongate member.

7. A hanger insert for installation in decking including a layer of concrete and a sheet member supporting,

the concrete prior to its being poured, and said insert comprising:

A. an elongate metal member having a bottom end and atop end,

' B. means for supporting said elongate metal member in a disposition passing through a hole ina sheet member which is adapted to have concrete poured onto the upper surface of the sheet member, with the bottom portion of theelongate metal member protruding below the sheet member, and the top portion of the elongate metal member protruding above the sheet member,

C. said elongate metal member including structure to" enable the securement of a structural member from the bottom portion thereof which structural mem-.

ber is adapted to depend from the decking to be formed, a D. a leaf spring formed of flat spring stock bowed about a central area and loosely mounted through said central area on said elongate member to'have its concave surface facing the lower portion of the elongate member, said bowed portion being lockable between the stop means on said elongate member and the upper surface of said sheet member to provide a yieldable connection between said hanger insert and sheet member prior to the setting of said concrete, said elongate member having stop,

means establishingthe location of mountinglsaid leaf spring thereon, and

E. said supporting means including a hollow sheath member telescopically engaged with said elongate metal member along a portion of the length thereof, the sheath member being adapted to be inserted through a predrilled hole in said sheet member of a size to accommodate said sheath member, the sheath member having means at the upper end thereof adapted resiliently to engage within the hole of said sheet member to resist the sheath members passing throughor being pulled from said sheet member while at the same time providing a yieldable connection therewith, and the lower end of the sheathmember being constructed to provide across to the bottom end of the elongate metal member after the concrete has been poured and set.

8. The hanger insert as claimed in claim 7, in which the said sheath member and elongate metal member have cooperating means limiting the extent to which the elongate member is telescopically insertable into the sheath member.

9. The hanger insert as claimed in claim 7,'in which said sheath member is of elastomeric material.

10. The hanger insert as claimed in claim 7, in which, the sheath member is made of sheet metal, and the,

means at the upper end thereof comprise an overhang adapted to engage the upper surface of the sheet member and means spaced below said overhang'adapted resiliently to engage with said sheet member on the lower surface thereof.

11. The hanger insert as claimed in claim 10, in

which said means adapted resiliently to engage said sheet member comprises a set of fingers circumferentially arranged around the sheath member and having 

1. A hanger insert for installation in decking including a layer of concrete and a sheet member supporting the concrete prior to its being poured, the insert comprising: A. an elongate metal member having a bottom end and a top end with stop means located therebetween, B. means for supporting said elongate metal member in a disposition passing through a hole in a sheet member which is adapted to have concrete poured onto the upper surface of the sheet member, with the bottom portion of the elongate metal member protruding below the sheet member and the top portion of the elongate metal member protruding above the sheet member, C. said elongate metal member including structure to enable thE securement of a structural member from the bottom portion thereof which structural member is adapted to depend from the decking to be formed, and D. a leaf spring formed of flat spring stock bowed about a central area and loosely mounted through said central area on said elongate member to have its concave surface facing the lower portion of the elongate member, said leaf spring being held between the stop means on said elongate member and the upper surface of said sheet member, said leaf spring providing a yieldable connection between said hanger insert and sheet member prior to the setting of said concrete and enabling the hanger insert to absorb the shock attendent upon the influx of fluid concrete and to restore the elongate metal member to an erect position before the concrete sets.
 2. The hanger insert as claimed in claim 1, in which said stop means comprise a formation on said upper portion integral with said elongate metal member, said leaf spring has a central opening in which said elongate metal member engages, and said formation is larger than said opening.
 3. The hanger insert as claimed in claim 1, in which the elongate metal member is a threaded bolt, the leaf spring has a central opening in which said bolt is engaged, and the stop member is a nut, the structure to enable securement comprising the bottom threaded end of said bolt.
 4. The hanger insert as claimed in claim 1, in which the upper end of said elongate metal member comprises an enlarged structure to provide embedment area greater than the cross-sectional area of said elongate metal member.
 5. The hanger insert as claimed in claim 1, in which the means for supporting the elongate member include a sleevelike sheet metal member secured on said lower portion and adapted to engage the bottom surface of said sheet member and clamp same between said leaf spring and itself.
 6. The hanger insert as claimed in claim 5, in which the ends of the leaf spring are turned slightly toward the upper portion of the elongate member.
 7. A hanger insert for installation in decking including a layer of concrete and a sheet member supporting the concrete prior to its being poured, and said insert comprising: A. an elongate metal member having a bottom end and a top end, B. means for supporting said elongate metal member in a disposition passing through a hole in a sheet member which is adapted to have concrete poured onto the upper surface of the sheet member, with the bottom portion of the elongate metal member protruding below the sheet member and the top portion of the elongate metal member protruding above the sheet member, C. said elongate metal member including structure to enable the securement of a structural member from the bottom portion thereof which structural member is adapted to depend from the decking to be formed, D. a leaf spring formed of flat spring stock bowed about a central area and loosely mounted through said central area on said elongate member to have its concave surface facing the lower portion of the elongate member, said bowed portion being lockable between the stop means on said elongate member and the upper surface of said sheet member to provide a yieldable connection between said hanger insert and sheet member prior to the setting of said concrete, said elongate member having stop means establishing the location of mounting said leaf spring thereon, and E. said supporting means including a hollow sheath member telescopically engaged with said elongate metal member along a portion of the length thereof, the sheath member being adapted to be inserted through a predrilled hole in said sheet member of a size to accommodate said sheath member, the sheath member having means at the upper end thereof adapted resiliently to engage within the hole of said sheet member to resist the sheath member''s passing through or being pulled from said sheet member while at the same time providing a yieldable connection therewith, and the lower end of the sheath member being constructed to provide across to the bottom end of the elongate metal member after the concrete has been poured and set.
 8. The hanger insert as claimed in claim 7, in which the said sheath member and elongate metal member have cooperating means limiting the extent to which the elongate member is telescopically insertable into the sheath member.
 9. The hanger insert as claimed in claim 7, in which said sheath member is of elastomeric material.
 10. The hanger insert as claimed in claim 7, in which the sheath member is made of sheet metal, and the means at the upper end thereof comprise an overhang adapted to engage the upper surface of the sheet member and means spaced below said overhang adapted resiliently to engage with said sheet member on the lower surface thereof.
 11. The hanger insert as claimed in claim 10, in which said means adapted resiliently to engage said sheet member comprises a set of fingers circumferentially arranged around the sheath member and having a given spacing from the overhang thereof whereby when inserted through said predrilled hole the fingers will be depressed and will then spring outwardly after passing through said hole whereby to sandwich the sheet member between said overhang and said fingers.
 12. The hanger insert as claimed in claim 9, in which the means at the upper end of the sheath member comprise groove means formed in the exterior surface thereof.
 13. The hanger insert as claimed in claim 12, in which the sheath member is tapered and the groove means are of increasing diameter along the length thereof.
 14. A hanger insert for installation in decking including a layer of concrete and a sheet member supporting the concrete prior to its being poured, the insert comprising: A. an elongate metal member having a bottom end and a top end, B. means for supporting said elongate metal member in a disposition passing through a hole in a sheet member which is adapted to have concrete poured onto the upper surface of the sheet member, with the bottom portion of the elongate metal member protruding below the sheet member and the top portion of the elongate metal member protruding above the sheet member, C. said elongate metal member including structure to enable the securement of a structural member from the bottom portion thereof which structural member is adapted to depend from the decking to be formed, D. a leaf spring formed of flat spring stock bowed about a central area and loosely mounted through said central area on said elongate member to have its concave surface facing the lower portion of the elongate member, said bowed portion being lockable between the stop means on said elongate member and the upper surface of said sheet member to provide a yieldable connection between said hanger insert and sheet member prior to the setting of said concrete, said elongate member having stop means establishing the location of mounting said leaf spring thereon, E. the means for supporting the elongate member including a sleevelike sheet metal member secured on said lower portion and adapted to engage the bottom surface of said sheet member and clamp same between said leaf spring and itself, F. the bottom portion of said elongate member is threaded and the sleevelike sheet metal member has thread-engaging tangs screwed onto said threaded end, and G. the sleevelike sheet metal member having flared resilient ears, capable of contracting while said sleevelike sheet metal member is forced through the hole in said sheet member and recovering thereafter.
 15. The hanger insert as claimed in claim 14, in which the position of the stop means is adjustable.
 16. A hanger insert for installation in sheet steel decking comprising: A. a boltlike member having a headed portion at one end and means for securement of a structural member at the other end, B. a flat bowed leaf spring having a central passageway between outer bowed ends, the bolt-like member bEing engaged in the passageway, the bow being concave toward said other end, C. stop means limiting movement of the spring along the central passageway toward said one end, and D. sleevelike means attached to said other end for mounting said boltlike member in a hole in a horizontal member of sheet steel with the bow ends of the leaf spring engaging the top of said horizontal member and the boltlike member making a yieldable but recoverable connection with said horizontal member.
 17. The hanger insert as claimed in claim 16, in which the sleevelike means comprises a tapered, molded, elastomeric sleeve having exterior annular groove means at its upper end of different sizes.
 18. The hanger insert as claimed in claim 16, in which the sleevelike means comprises a sheet metal nut adapted to engage the bottom of said horizontal member.
 19. The hanger insert as claimed in claim 18, in which the boltlike member is a threaded bolt and the securement means is the threaded end opposite said headed portion.
 20. In combination with the sheet steel member of a steel floor deck, a hanger insert engaged in a predrilled hole in said sheet steel member with a part of the insert disposed above the sheet steel member and other part of the insert disposed below the sheet steel member, said insert comprising: A. an elongate cylindrical member of metal having an upper portion and a lower portion, the upper portion having a head adapted to be embedded in concrete poured on the upper surface of said sheet steel member, the lower portion having a formation to enable the securement of a structural member thereto depending from the bottom of said sheet steel member, B. a flat leaf spring having a central connection with the upper portion of said cylindrical member and stop means limiting the movement of the spring toward said head, the spring being bowed concavely toward the lower portion with its ends engaging the upper surface of said sheet steel member, and C. a sleevelike sheet metal member secured to the lower portion in telescoping engagement and effective in cooperation with the spring to hold said cylindrical member in a yieldable but recoverable disposition normal to the plane of said sheet steel member.
 21. The combination as claimed in claim 20, in which the distance between the stop means and sleevelike sheet metal member is such as to put the leaf spring under at least partial tension and the tension is adjustable.
 22. The combination as claimed in claim 20, in which the cylindrical member is a threaded bolt, the stop means is a nut and the sleevelike member is a sheet metal nut. 